A security power supply system for a power plant with a double-unit configuration and its working method

Abstract

The present invention discloses a security power supply system for a power plant with a double-unit configuration and its working method, including the turbine PC A section of Unit #1, the turbine PC A section of Unit #2, the feeder switch of the turbine PC A section of Unit #1, the feeder switch of the turbine PC A section of Unit #2, the first working incoming line switch of the security PC A section of Unit #1, the second working incoming line switch of the security PC A section of Unit #1, the automatic standby power supply device of the security PC A section of Unit #1, the busbar of the security PC A section of Unit #1, the busbar voltage transformer of the security PC A section of Unit #1, the standby incoming line switch of the security PC A section of Unit #1, the feeder switch of the standby busbar of the security standby PC section of Unit #1, the incoming line switch of the standby busbar of the security standby PC section of Unit #1, the standby busbar of the security standby PC section of Unit #1, the outlet circuit breaker of the diesel generator of Unit #1, the diesel generator of Unit #1, the generator-transformer protection device of Unit #1, and the fast transfer device of the auxiliary power supply A section of Unit #1. This system and its working method can improve the reliability and rapid response of the security power supply system of thermal power units.

Description

Technical Field

[0001] The present invention belongs to the technical field of auxiliary power systems on the power generation side, and relates to a security power supply system for a power plant with a dual-unit configuration and its working method. Background Art

[0002] After the normal auxiliary power of the unit in a power plant is lost, the security load of the unit will directly endanger the safety of the unit, and even cause permanent damage, resulting in huge economic losses. To avoid such accidents, a specially set security section is usually used to supply power to it centrally.

[0003] GB 50660-2011 "Design Code for Large and Medium-sized Thermal Power Plants" stipulates in the form of mandatory articles that units with a capacity of 200 MW and above should be equipped with an AC security power supply, and it is clear that the AC security power supply should use a diesel generator set with quick start. DLT5153-2014 "Technical Code for Auxiliary Power Design of Thermal Power Plants" requires that the AC security busbar should adopt a single-busbar connection, be segmented by unit, and supply the AC security load of this unit respectively. During normal operation, the security busbar section should be powered by the low-voltage explicit or implicit standby power center of this unit. When it is confirmed that the power center of this unit has truly lost power, it should be able to switch to the AC security power supply.

[0004] In practical applications, relatively serious accidents have occurred when only supplying the AC security load of this unit by segmenting according to the unit. When a similar grounding fault occurs in the auxiliary power busbar of this unit, after the zero-sequence protection action, the auxiliary power fast transfer will be blocked and other standby auxiliary power sources cannot be switched into the auxiliary power busbar of this unit. At this time, both the low-voltage explicit or implicit standby power centers of this unit will lose the power supply. When the security power supply starts the diesel generator after judging voltage loss in the backup power supply automatic switching device, since the voltage buildup time of the diesel generator is relatively long, generally about 10 to 15 seconds, the voltage of the security busbar drops significantly at this time. When the diesel generator is connected to the security section busbar for power supply, it will fail to carry the load due to excessive load current, resulting in serious consequences such as the unit running out of oil and burning the bearings.

[0005] In addition, there is another situation. When the line protection trips or trips secretly, this unit and all adjacent units will shed loads and maintain island operation. At this time, when the unit cannot maintain the operating state for a long time, it will trip and cause a power outage of the whole plant. At this time, only the diesel generator can supply power to the security section load, and the safety and reliability of the security power supply system are particularly important. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and provides a security power supply system for a power plant with a dual-unit configuration and its working method. This system and its working method can improve the reliability and rapid response of the security power supply system of thermal power units.

[0007] To achieve the above object, the emergency power supply system of the power plant configured with a dual-unit set includes the turbine PC A section of Unit #1, the turbine PC A section of Unit #2, the feeder switch of the turbine PC A section of Unit #1, the feeder switch of the turbine PC A section of Unit #2, the first working incoming line switch of the emergency PC A section of Unit #1, the second working incoming line switch of the emergency PC A section of Unit #1, the automatic standby power switching device of the emergency PC A section of Unit #1, the busbar of the emergency PC A section of Unit #1, the busbar voltage transformer of the emergency PC A section of Unit #1, the standby incoming line switch of the emergency PC A section of Unit #1, the feeder switch of the standby emergency PC section busbar of Unit #1, the incoming line switch of the standby emergency PC section busbar of Unit #1, the standby emergency PC section busbar of Unit #1, the outlet circuit breaker of the diesel generator of Unit #1, the diesel generator of Unit #1, the generator-transformer unit protection device of Unit #1, and the fast transfer device of the auxiliary power supply A section of Unit #1;

[0008] The turbine PC A section of Unit #1 is connected to the busbar of the emergency PC A section of Unit #1 through the feeder switch of the turbine PC A section of Unit #1 and the first working incoming line switch of the emergency PC A section of Unit #1;

[0009] The turbine PC A section of Unit #2 is connected to the busbar of the emergency PC A section of Unit #1 through the feeder switch of the turbine PC A section of Unit #2 and the second working incoming line switch of the emergency PC A section of Unit #1;

[0010] The diesel generator of Unit #1 is connected to the standby emergency PC section busbar of Unit #1 through the outlet circuit breaker of the diesel generator of Unit #1 and the incoming line switch of the standby emergency PC section busbar of Unit #1;

[0011] The standby emergency PC section busbar of Unit #1 is connected to the busbar of the emergency PC A section of Unit #1 through the feeder switch of the standby emergency PC section busbar of Unit #1 and the standby incoming line switch of the emergency PC A section of Unit #1;

[0012] The output end of the automatic standby power switching device of the emergency PC A section of Unit #1 is connected to the control ends of the first working incoming line switch of the emergency PC A section of Unit #1, the second working incoming line switch of the emergency PC A section of Unit #1, and the incoming line switch of the standby emergency PC section busbar of Unit #1;

[0013] The output end of the automatic standby power switching device of the emergency PC A section of Unit #1, the output end of the fast transfer device of the auxiliary power supply A section of Unit #1, and the output end of the generator-transformer unit protection device of Unit #1 are all connected to the control end of the diesel generator of Unit #1.

[0014] It also includes the voltage transformer of the first working incoming line switch of the emergency PC A section of Unit #1; the voltage transformer of the first working incoming line switch of the emergency PC A section of Unit #1 is installed on the line between the first working incoming line switch of the emergency PC A section of Unit #1 and the feeder switch of the turbine PC A section of Unit #1.

[0015] It also includes the second voltage transformer of the working incoming switch of the #1 unit security PC A section; the second voltage transformer of the working incoming switch of the #1 unit security PC A section is installed on the line between the second working incoming switch of the #1 unit security PC A section and the feeder switch of the #2 unit turbine PC A section.

[0016] It also includes the bus voltage transformer of the #1 unit security standby PC section; the bus voltage transformer of the #1 unit security standby PC section is installed on the bus of the #1 unit security standby PC section.

[0017] It also includes the bus voltage transformer of the #1 unit security PC A section; the bus voltage transformer of the #1 unit security PC A section is installed on the bus of the #1 unit security PC A section.

[0018] The input end of the #1 security PC A section bus transfer switch device is connected to the bus voltage transformer of the #1 unit security standby PC section, the bus voltage transformer of the #1 unit security PC A section, the second voltage transformer of the working incoming switch of the #1 unit security PC A section, and through the first voltage transformer of the working incoming switch of the #1 unit security PC A section.

[0019] The working method of the security power supply system of the power plant configured with dual sets of units described in the present invention includes the following steps:

[0020] 1) The #1 unit and the #2 unit are in normal operation, the voltages of the #1 unit turbine PC A section and the #2 unit turbine PC A section are normal, and the voltage of the #1 unit security PC A section bus is normal;

[0021] 2) Put the feeder switch of the #1 unit turbine PC A section and the feeder switch of the #2 unit turbine PC A section in the closed position, put the first working incoming switch of the #1 unit security PC A section in the closed position, put the second working incoming switch of the #1 unit security PC A section in the open position, and the #1 unit security PC A section bus is normally powered by the #1 unit turbine PC A section;

[0022] 3) Put the feeder switch of the #1 unit security standby PC section bus in the closed position, put the incoming switch of the #1 unit security standby PC section bus in the closed position, put the standby incoming switch of the #1 unit security PC A section in the open position, put the outlet circuit breaker of the #1 unit diesel generator in the open position, and the #1 unit diesel generator is in hot standby;

[0023] 4) Put into the #1 security PC A section bus transfer switch device, put into the #1 unit auxiliary power A section fast transfer device, and the #1 unit generator-transformer unit protection device is in normal operation;

[0024] 5) When the PC A section of the turbine of Unit 1 loses power, or when the feeder switch of the PC A section of the turbine of Unit 1 and the working incoming switch of the emergency PC A section of Unit 1 trip simultaneously, causing the busbar of the emergency PC A section of Unit 1 to lose voltage, the backup power supply automatic switching device of the emergency PC A section of Unit 1 issues a busbar voltage loss start signal to start the diesel generator of Unit 1. The diesel generator of Unit 1 starts and builds voltage. After successful voltage build-up, the outlet circuit breaker of the diesel generator of Unit 1 is automatically closed.

[0025] 6) The backup power supply automatic switching device of the emergency PC A section of Unit 1 checks whether the voltage detected by the voltage transformer of the second working incoming switch of the emergency PC A section of Unit 1 is normal. If the voltage detected by the voltage transformer of the second working incoming switch of the emergency PC A section of Unit 1 is normal, it proceeds to step 7); otherwise, it proceeds to step 14).

[0026] 7) The backup power supply automatic switching device of the emergency PC A section of Unit 1 disconnects the first working incoming switch of the emergency PC A section of Unit 1 and closes the second working incoming switch of the emergency PC A section of Unit 1.

[0027] 8) The backup power supply automatic switching device of the emergency PC A section of Unit 1 checks whether the voltage detected by the voltage transformer of the busbar of the emergency PC A section of Unit 1 is normal. If the voltage detected by the voltage transformer of the busbar of the emergency PC A section of Unit 1 is normal, it proceeds to step 9); otherwise, it proceeds to step 10).

[0028] 9) Trip the outlet circuit breaker of the diesel generator of Unit 1 and stop the diesel generator of Unit 1. The PC A section 2 of the turbine of Unit 2 supplies power to the busbar of the emergency PC A section of Unit 1.

[0029] 10) The backup power supply automatic switching device of the emergency PC A section of Unit 1 disconnects the second working incoming switch of the emergency PC A section of Unit 1.

[0030] 11) Check whether the voltage of the emergency standby PC section busbar of Unit 1 is normal. If the voltage of the emergency standby PC section busbar of Unit 1 is normal, it proceeds to step 12); otherwise, it proceeds to step 13).

[0031] 12) The backup power supply automatic switching device of the emergency PC A section of Unit 1 closes the standby incoming switch of the emergency PC A section of Unit 1. The diesel generator of Unit 1 supplies power to the busbar of the emergency PC A section of Unit 1.

[0032] 13) Disconnect the standby incoming switch of the emergency PC A section of Unit 1, check the defects of the diesel generator of Unit 1, and after eliminating the defects, close the standby incoming switch of the emergency PC A section of Unit 1. The diesel generator of Unit 1 supplies power to the busbar of the emergency PC A section of Unit 1.

[0033] 14) Confirm the automatic switching device for the standby power supply of Section A of the #1 unit's security PC. Disconnect the second working incoming switch of Section A of the #1 unit's security PC.

[0034] 15) Check whether the voltage of the busbar of the standby security PC section of the #1 unit is normal. When the voltage of the busbar of the standby security PC section of the #1 unit is normal, proceed to step 16); otherwise, proceed to step 17).

[0035] 16) The automatic switching device for the standby power supply of Section A of the #1 unit's security PC closes the standby incoming switch 12 of Section A of the #1 unit's security PC, and the #1 unit's diesel generator supplies power to the busbar of Section A of the #1 unit's security PC.

[0036] 17) Check the defects of the #1 unit's diesel generator. After eliminating the defects, close the standby incoming switch of Section A of the #1 unit's security PC, and the #1 unit's diesel generator supplies power to the busbar of Section A of the #1 unit's security PC.

[0037] 18) When the fast transfer is blocked due to the grounding fault of the auxiliary busbar of the #1 unit and the auxiliary busbar of the #1 unit loses power, after the fast transfer device of Section A of the #1 unit's auxiliary busbar sends out the action signal of fast transfer blocking, start the #1 unit's diesel generator to build pressure. After the pressure building is successful, automatically close the outlet circuit breaker of the #1 unit's diesel generator, and then proceed to step 6).

[0038] 19) When the whole plant loses power after the #1 unit and the #2 unit shed load due to the external line being tripped secretly or the line protection tripping, the zero-power generator tripping protection action signal sent by the generator-transformer protection device of the #1 unit starts the #1 unit's diesel generator to build pressure. After the pressure building is successful, close the outlet circuit breaker of the #1 unit's diesel generator, and then proceed to step 6).

[0039] The present invention has the following beneficial effects:

[0040] When the security power supply system of the power plant with double-unit configuration and its working method according to the present invention are specifically operated, the auxiliary power supplies of the power plant with double-unit configuration are used to supply power to the security power supply system in a cross manner to increase the safety redundancy of the security power supply system. At the same time, the starting mode of the diesel generator of the security power supply system is improved, and the diesel generator is started to build pressure in advance before the standby power supply automatic switching device detects the loss of voltage of the security section busbar, which can greatly improve the reliability and rapid response of the security power supply system of thermal power units. Brief Description of the Drawings

[0041] Figure 1 is a structural schematic diagram of the present invention;

[0042] Figure 2 is a flow chart of the present invention.

[0043] Among them, 1 is the turbine PC A section of Unit #1, 2 is the turbine PC A section of Unit #2, 3 is the feeder switch of the turbine PC A section of Unit #1, 4 is the feeder switch of the turbine PC A section of Unit #2, 5 is the voltage transformer of the working incoming line switch 1 of the emergency power supply PC A section of Unit #1, 6 is the voltage transformer of the working incoming line switch 2 of the emergency power supply PC A section of Unit #1, 7 is the working incoming line switch 1 of the emergency power supply PC A section of Unit #1, 8 is the working incoming line switch 2 of the emergency power supply PC A section of Unit #1, 9 is the automatic standby power supply device of the emergency power supply PC A section of Unit #1, 10 is the busbar of the emergency power supply PC A section of Unit #1, 11 is the busbar voltage transformer of the emergency power supply PC A section of Unit #1, 12 is the standby incoming line switch of the emergency power supply PC A section of Unit #1, 13 is the feeder switch of the standby busbar of the emergency power supply PC section of Unit #1, 14 is the busbar voltage transformer of the standby busbar of the emergency power supply PC section of Unit #1, 15 is the incoming line switch of the standby busbar of the emergency power supply PC section of Unit #1, 16 is the standby busbar of the emergency power supply PC section of Unit #1, 17 is the outlet circuit breaker of the diesel generator of Unit #1, 18 is the diesel generator of Unit #1, 19 is the generator-transformer unit protection device of Unit #1, and 20 is the fast transfer switch device of the auxiliary power supply A section of Unit #1. Detailed implementation manners

[0044] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present invention disclosure. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessarily confusing the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0045] The structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures and their relative sizes and positional relationships are only exemplary, and may actually deviate due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0046] Refer to Figure 1, the emergency power supply system of the power plant with a dual-unit configuration described in the present invention includes the turbine PCA section 1 of Unit #1, the turbine PC A section 2 of Unit #2, the feeder switch 3 of the turbine PC A section of Unit #1, the feeder switch 4 of the turbine PC A section of Unit #2, the working incoming line switch No. 1 voltage transformer 5 of the emergency PC A section of Unit #1, the working incoming line switch No. 2 voltage transformer 6 of the emergency PC A section of Unit #1, the working incoming line switch No. 1 7 of the emergency PC A section of Unit #1, the working incoming line switch No. 2 8 of the emergency PC A section of Unit #1, the standby power supply automatic switching device 9 of the emergency PC A section of Unit #1, the busbar 10 of the emergency PC A section of Unit #1, the busbar voltage transformer 11 of the emergency PC A section of Unit #1, the standby incoming line switch 12 of the emergency PC A section of Unit #1, the feeder switch 13 of the standby PC section busbar of Unit #1, the busbar voltage transformer 14 of the standby PC section busbar of Unit #1, the incoming line switch 15 of the standby PC section busbar of Unit #1, the standby PC section busbar 16 of Unit #1, the outlet circuit breaker 17 of the diesel generator of Unit #1, the diesel generator 18 of Unit #1, the generator-transformer unit protection device 19 of Unit #1, and the fast transfer device 20 of the auxiliary power supply A section of Unit #1;

[0047] The turbine PCA section 1 of Unit #1 is connected to the busbar 10 of the emergency PC A section of Unit #1 through the feeder switch 3 of the turbine PC A section of Unit #1 and the working incoming line switch No. 1 7 of the emergency PC A section of Unit #1. The working incoming line switch No. 1 voltage transformer 5 of the emergency PC A section of Unit #1 is installed on the line between the working incoming line switch No. 1 7 of the emergency PC A section of Unit #1 and the feeder switch 3 of the turbine PC A section of Unit #1, and samples the voltage value of the working incoming line switch No. 1 7 of the emergency PC A section of Unit #1 through the working incoming line switch No. 1 voltage transformer 5 of the emergency PC A section of Unit #1;

[0048] The turbine PC A section 2 of Unit #2 is connected to the busbar 10 of the emergency PC A section of Unit #1 through the feeder switch 4 of the turbine PC A section of Unit #2 and the working incoming line switch No. 2 8 of the emergency PC A section of Unit #1. The working incoming line switch No. 2 voltage transformer 6 of the emergency PC A section of Unit #1 is installed on the line between the working incoming line switch No. 2 8 of the emergency PC A section of Unit #1 and the feeder switch 4 of the turbine PC A section of Unit #2, and samples the voltage value of the working incoming line switch No. 2 8 of the emergency PC A section of Unit #1 through the working incoming line switch No. 2 voltage transformer 6 of the emergency PC A section of Unit #1;

[0049] The busbar voltage transformer 11 of the emergency PC A section of Unit #1 is installed on the busbar 10 of the emergency PC A section of Unit #1, and samples the voltage of the busbar 10 of the emergency PC A section of Unit #1 through the busbar voltage transformer 11 of the emergency PC A section of Unit #1;

[0050] The diesel generator 18 of Unit #1 is connected to the emergency standby PC busbar 16 of Unit #1 through the outlet circuit breaker 17 of the diesel generator of Unit #1 and the incoming line switch 15 of the emergency standby PC busbar of Unit #1. The voltage transformer 14 of the emergency standby PC busbar of Unit #1 is installed on the emergency standby PC busbar 16 of Unit #1, and samples the voltage of the emergency standby PC busbar 16 of Unit #1 through the voltage transformer 14 of the emergency standby PC busbar of Unit #1;

[0051] The emergency standby PC busbar 16 of Unit #1 is connected to the emergency standby PC busbar A 10 of Unit #1 through the feeder switch 13 of the emergency standby PC busbar of Unit #1 and the incoming line switch 12 of the emergency standby PC A section of Unit #1;

[0052] The input end of the automatic switching device 9 for the emergency standby PC A section of Unit #1 is connected to the voltage transformer 14 of the emergency standby PC busbar of Unit #1, the voltage transformer 11 of the emergency standby PC busbar A of Unit #1, the voltage transformer 6 of the second incoming line switch of the working power supply of the emergency standby PC A section of Unit #1, and the voltage transformer 5 of the first incoming line switch of the working power supply of the emergency standby PC A section of Unit #1 through the voltage transformer 5 of the first incoming line switch of the working power supply of the emergency standby PC A section of Unit #1. The output end of the automatic switching device 9 for the emergency standby PC A section of Unit #1 is connected to the control ends of the first incoming line switch 7 of the working power supply of the emergency standby PC A section of Unit #1, the second incoming line switch 8 of the working power supply of the emergency standby PC A section of Unit #1, and the incoming line switch 15 of the emergency standby PC busbar of Unit #1.

[0053] The output end of the generator-transformer unit protection device 19 of Unit #1 is connected to the control end of the diesel generator 18 of Unit #1. When the diesel generator 18 of Unit #1 receives the zero-power generator tripping protection action signal issued by the generator-transformer unit protection device 19 of Unit #1, it starts to build voltage;

[0054] The output end of the fast transfer device 20 for the auxiliary power supply A section of Unit #1 is connected to the control end of the diesel generator 18 of Unit #1. When the diesel generator 18 of Unit #1 receives the action signal of fast transfer locking issued by the fast transfer device 20 for the auxiliary power supply A section of Unit #1, it starts to build voltage;

[0055] The output end of the automatic switching device 9 for the emergency standby PC A section of Unit #1 is connected to the control end of the diesel generator 18 of Unit #1. When the diesel generator 18 of Unit #1 receives the voltage loss signal of the emergency standby PC busbar A 10 of Unit #1 issued by the automatic switching device 9 for the emergency standby PC A section of Unit #1, it starts to build voltage;

[0056] The wiring of the emergency power supply system for the B section of Unit #1 and the emergency power supply systems for the A and B sections of Unit #2 are the same as the above structure.

[0057] Reference Figure 2 , The working method of the emergency power supply system for a power plant with a dual-unit configuration described in the present invention includes the following steps:

[0058] 1) Unit #1 and Unit #2 are operating normally. The voltages of Turbine PC A Section 1 of Unit #1 and Turbine PC A Section 2 of Unit #2 are normal, and the voltage of the Emergency Power Supply PC A Section Bus 10 of Unit #1 is normal.

[0059] 2) Put the feeder switch 3 of Turbine PC A Section of Unit #1 and the feeder switch 4 of Turbine PC A Section of Unit #2 in the closed position. Put the working incoming line switch 7 of the Emergency Power Supply PC A Section of Unit #1 in the closed position, and put the working incoming line switch 8 of the Emergency Power Supply PC A Section of Unit #1 in the open position. The Emergency Power Supply PC A Section Bus 10 of Unit #1 is normally powered by Turbine PC A Section 1 of Unit #1.

[0060] 3) Put the feeder switch 13 of the Emergency Power Supply Standby PC Section Bus of Unit #1 in the closed position, put the incoming line switch 15 of the Emergency Power Supply Standby PC Section Bus of Unit #1 in the closed position, put the standby incoming line switch 12 of the Emergency Power Supply PC A Section of Unit #1 in the open position, and put the outlet circuit breaker 17 of the diesel generator of Unit #1 in the open position. The diesel generator 18 of Unit #1 is in hot standby.

[0061] 4) The automatic switching device 9 of the Emergency Power Supply PC A Section of Unit #1 is put into operation, the fast transfer device 20 of the Auxiliary Power Supply A Section of Unit #1 is put into operation, and the generator-transformer unit protection device 19 of Unit #1 is operating normally.

[0062] 5) When Turbine PC A Section 1 of Unit #1 loses power or the feeder switch 3 of Turbine PC A Section of Unit #1 and the working incoming line switch 7 of the Emergency Power Supply PC A Section of Unit #1 trip accidentally, resulting in the loss of voltage of the Emergency Power Supply PC A Section Bus 10 of Unit #1, the automatic switching device 9 of the Emergency Power Supply PC A Section of Unit #1 sends out a bus loss-of-voltage start signal to start the diesel generator 18 of Unit #1. After the diesel generator 18 of Unit #1 starts and builds up voltage, the outlet circuit breaker 17 of the diesel generator of Unit #1 is automatically closed.

[0063] 6) The automatic switching device 9 of the Emergency Power Supply PC A Section of Unit #1 checks whether the voltage detected by the voltage transformer 6 of the working incoming line switch 8 of the Emergency Power Supply PC A Section of Unit #1 is normal. If the voltage detected by the voltage transformer 6 of the working incoming line switch 8 of the Emergency Power Supply PC A Section of Unit #1 is normal, go to step 7); otherwise, go to step 14).

[0064] 7) The automatic switching device 9 of the Emergency Power Supply PC A Section of Unit #1 disconnects the working incoming line switch 7 of the Emergency Power Supply PC A Section of Unit #1. After the working incoming line switch 7 of the Emergency Power Supply PC A Section of Unit #1 is disconnected, the working incoming line switch 8 of the Emergency Power Supply PC A Section of Unit #1 is closed.

[0065] 8) The automatic switching device for the standby power supply of Section A of the #1 security PC checks whether the voltage detected by the voltage transformer 11 of the busbar of Section A of the #1 security PC is normal. If the voltage detected by the voltage transformer 11 of the busbar of Section A of the #1 security PC is normal, then go to step 9); otherwise, go to step 10).

[0066] 9) Trip the outlet circuit breaker 17 of the #1 unit diesel generator, stop the #1 unit diesel generator 18, and supply power to the busbar 10 of Section A of the #1 security PC from Section A of the turbine PC of the #2 unit.

[0067] 10) The automatic switching device for the standby power supply of Section A of the #1 security PC disconnects the working incoming switch II 8 of Section A of the #1 security PC.

[0068] 11) Check whether the voltage of the standby busbar 16 of Section A of the #1 security PC is normal. When the voltage of the standby busbar 16 of Section A of the #1 security PC is normal, then go to step 12); otherwise, go to step 13).

[0069] 12) The automatic switching device for the standby power supply of Section A of the #1 security PC closes the standby incoming switch 12 of Section A of the #1 security PC, and the #1 unit diesel generator 18 supplies power to the busbar 10 of Section A of the #1 security PC.

[0070] 13) Disconnect the standby incoming switch 12 of Section A of the #1 security PC, check the defects of the #1 unit diesel generator 18, and after eliminating the defects, close the standby incoming switch 12 of Section A of the #1 security PC, and the #1 unit diesel generator 18 supplies power to the busbar 10 of Section A of the #1 security PC.

[0071] 14) The automatic switching device for the standby power supply of Section A of the #1 security PC confirms that the working incoming switch II 8 of Section A of the #1 security PC is disconnected.

[0072] 15) Check whether the voltage of the standby busbar 16 of Section A of the #1 security PC is normal. When the voltage of the standby busbar 16 of Section A of the #1 security PC is normal, then go to step 16); otherwise, go to step 17).

[0073] 16) The automatic switching device for the standby power supply of Section A of the #1 security PC closes the standby incoming switch 12 of Section A of the #1 security PC, and the #1 unit diesel generator 18 supplies power to the busbar 10 of Section A of the #1 security PC.

[0074] 17) Check the defects of the #1 unit diesel generator 18, and after eliminating the defects, close the standby incoming switch 12 of Section A of the #1 security PC, and the #1 unit diesel generator 18 supplies power to the busbar 10 of Section A of the #1 security PC.

[0075] 18) When the fast transfer is blocked due to the grounding fault of the auxiliary bus of Unit #1 and the auxiliary bus of Unit #1 loses power, after the fast transfer device 20 of the auxiliary A section of Unit #1 issues a signal for the fast transfer blocking action, it starts the voltage building of the diesel generator 18 of Unit #1. After the voltage building is successful, the outlet circuit breaker 17 of the diesel generator of Unit #1 is automatically closed, and then it turns to step 6);

[0076] 19) When the whole plant loses power after Unit #1 and Unit #2 shed loads due to the unauthorized tripping of an external line or the tripping of the line protection, the generator-transformer protection device 19 of Unit #1 issues a signal for the zero-power generator tripping protection action to start the voltage building of the diesel generator 18 of Unit #1. After the voltage building is successful, the outlet circuit breaker 17 of the diesel generator of Unit #1 is closed, and then it turns to step 6).

[0077] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. In addition, power plants with similar dual-unit configurations or newly built plants and old plants after expansion, as long as there are adjacent units in the power plant, can refer to this system configuration.

Claims

1. A working method of a security power supply system for a power plant with a double-unit configuration, characterized in that, The emergency power supply system of the power plant configured with a dual-unit set includes the Turbine PC A Section of Unit #1 (1), the Turbine PC A Section of Unit #2 (2), the feeder switch of the Turbine PC A Section of Unit #1 (3), the feeder switch of the Turbine PC A Section of Unit #2 (4), the first working incoming line switch of the Emergency PC A Section of Unit #1 (7), the second working incoming line switch of the Emergency PC A Section of Unit #1 (8), the automatic standby power supply device of the Emergency PC A Section of Unit #1 (9), the busbar of the Emergency PC A Section of Unit #1 (10), the busbar voltage transformer of the Emergency PC A Section of Unit #1 (11), the standby incoming line switch of the Emergency PC A Section of Unit #1 (12), the feeder switch of the standby busbar of the Emergency PC Section of Unit #1 (13), the incoming line switch of the standby busbar of the Emergency PC Section of Unit #1 (15), the standby busbar of the Emergency PC Section of Unit #1 (16), the outlet circuit breaker of the diesel generator of Unit #1 (17), the diesel generator of Unit #1 (18), the generator-transformer unit protection device of Unit #1 (19), and the fast transfer device of the Auxiliary Power A Section of Unit #1 (20); The Turbine PC A Section of Unit #1 (1) is connected to the busbar of the Emergency PC A Section of Unit #1 (10) through the feeder switch of the Turbine PC A Section of Unit #1 (3) and the first working incoming line switch of the Emergency PC A Section of Unit #1 (7); The Turbine PC A Section of Unit #2 (2) is connected to the busbar of the Emergency PC A Section of Unit #1 (10) through the feeder switch of the Turbine PC A Section of Unit #2 (4) and the second working incoming line switch of the Emergency PC A Section of Unit #1 (8); The diesel generator of Unit #1 (18) is connected to the standby busbar of the Emergency PC Section of Unit #1 (16) through the outlet circuit breaker of the diesel generator of Unit #1 (17) and the incoming line switch of the standby busbar of the Emergency PC Section of Unit #1 (15); The standby busbar of the Emergency PC Section of Unit #1 (16) is connected to the busbar of the Emergency PC A Section of Unit #1 (10) through the feeder switch of the standby busbar of the Emergency PC Section of Unit #1 (13) and the standby incoming line switch of the Emergency PC A Section of Unit #1 (12); The output end of the automatic standby power supply device of the Emergency PC A Section of Unit #1 (9) is connected to the control ends of the first working incoming line switch of the Emergency PC A Section of Unit #1 (7), the second working incoming line switch of the Emergency PC A Section of Unit #1 (8), and the incoming line switch of the standby busbar of the Emergency PC Section of Unit #1 (15); The output end of the automatic standby power supply device of the Emergency PC A Section of Unit #1 (9), the output end of the fast transfer device of the Auxiliary Power A Section of Unit #1 (20), and the output end of the generator-transformer unit protection device of Unit #1 (19) are all connected to the control end of the diesel generator of Unit #1 (18); It also includes the voltage transformer of the first working incoming line switch of the Emergency PC A Section of Unit #1 (5); the voltage transformer of the first working incoming line switch of the Emergency PC A Section of Unit #1 (5) is installed on the line between the first working incoming line switch of the Emergency PC A Section of Unit #1 (7) and the feeder switch of the Turbine PC A Section of Unit #1 (3); It also includes the second voltage transformer (6) of the working incoming switch of the #1 unit's security PC A section; the second voltage transformer (6) of the working incoming switch of the #1 unit's security PC A section is installed on the line between the second working incoming switch (8) of the #1 unit's security PC A section and the feeder switch (4) of the #2 unit's turbine PC A section; It also includes the bus voltage transformer (14) of the #1 unit's security standby PC section; the bus voltage transformer (14) of the #1 unit's security standby PC section is installed on the bus (16) of the #1 unit's security standby PC section; It also includes the bus voltage transformer (11) of the #1 unit's security PC A section; the bus voltage transformer (11) of the #1 unit's security PC A section is installed on the bus (10) of the #1 unit's security PC A section; The input end of the #1 security PC A section automatic switching device (9) is connected to the bus voltage transformer (14) of the #1 unit's security standby PC section, the bus voltage transformer (11) of the #1 unit's security PC A section, the second voltage transformer (6) of the working incoming switch of the #1 unit's security PC A section, and is connected through the first voltage transformer (5) of the working incoming switch of the #1 unit's security PC A section; It includes the following steps: 1) The #1 unit and the #2 unit are operating normally, the voltages of the #1 unit's turbine PC A section (1) and the #2 unit's turbine PC A section (2) are normal, and the voltage of the #1 unit's security PC A section bus (10) is normal; 2) Put the feeder switch (3) of the #1 unit's turbine PC A section and the feeder switch (4) of the #2 unit's turbine PC A section in the closed position, put the first working incoming switch (7) of the #1 unit's security PC A section in the closed position, put the second working incoming switch (8) of the #1 unit's security PC A section in the open position, and the #1 unit's security PC A section bus (10) is normally powered by the #1 unit's turbine PC A section (1); 3) Put the feeder switch (13) of the #1 unit's security standby PC section bus in the closed position, put the incoming switch (15) of the #1 unit's security standby PC section bus in the closed position, put the standby incoming switch (12) of the #1 unit's security PC A section in the open position, put the outlet circuit breaker (17) of the #1 unit's diesel generator in the open position, and the #1 unit's diesel generator (18) is in hot standby; 4) Put into the #1 security PC A section automatic switching device (9), put into the fast switching device (20) of the #1 unit's auxiliary power A section, and the generator-transformer unit protection device (19) of the #1 unit operates normally; 5) When the #1 unit's turbine PC A section (1) loses power or the feeder switch (3) of the #1 unit's turbine PC A section and the first working incoming switch (7) of the #1 unit's security PC A section trip secretly, causing the #1 unit's security PC A section bus (10) to lose voltage, the #1 security PC A section automatic switching device (9) issues a bus loss-of-voltage start signal to start the #1 unit's diesel generator (18), the #1 unit's diesel generator (18) starts to build voltage, and after the voltage build-up is successful, it automatically closes the outlet circuit breaker (17) of the #1 unit's diesel generator; 6) The #1 security PC A section backup power supply automatic switching device (9) checks whether the voltage detected by the second voltage transformer (6) of the working incoming line switch of the #1 unit security PC A section is normal. If the voltage detected by the second voltage transformer (6) of the working incoming line switch of the #1 unit security PC A section is normal, go to step 7); otherwise, go to step 14). 7) The #1 security PC A section backup power supply automatic switching device (9) disconnects the first working incoming line switch (7) of the #1 unit security PC A section and closes the second working incoming line switch (8) of the #1 unit security PC A section. 8) The #1 security PC A section backup power supply automatic switching device (9) checks whether the voltage detected by the bus voltage transformer (11) of the #1 unit security PC A section is normal. If the voltage detected by the bus voltage transformer (11) of the #1 unit security PC A section is normal, go to step 9); otherwise, go to step 10). 9) Trip the outlet circuit breaker (17) of the #1 unit diesel generator, stop the #1 unit diesel generator (18), and supply power to the bus (10) of the #1 unit security PC A section by the #2 unit steam turbine PC A section (2). 10) The #1 security PC A section backup power supply automatic switching device (9) disconnects the second working incoming line switch (8) of the #1 unit security PC A section. 11) Check whether the voltage of the #1 unit security standby PC section bus (16) is normal. If the voltage of the #1 unit security standby PC section bus (16) is normal, go to step 12); otherwise, go to step 13). 12) The #1 security PC A section backup power supply automatic switching device (9) closes the standby incoming line switch (12) of the #1 unit security PC A section, and the #1 unit diesel generator (18) supplies power to the bus (10) of the #1 unit security PC A section. 13) Disconnect the standby incoming line switch (12) of the #1 unit security PC A section, check the defects of the #1 unit diesel generator (18), and after eliminating the defects, close the standby incoming line switch (12) of the #1 unit security PC A section, and the #1 unit diesel generator (18) supplies power to the bus (10) of the #1 unit security PC A section. 14) The #1 security PC A section backup power supply automatic switching device (9) confirms that the second working incoming line switch (8) of the #1 unit security PC A section is disconnected. 15) Check whether the voltage of the #1 unit security standby PC section bus (16) is normal. If the voltage of the #1 unit security standby PC section bus (16) is normal, go to step 16); otherwise, go to step 17). 16) The #1 security PC A section backup power supply automatic switching device (9) closes the standby incoming line switch (12) of the #1 unit security PC A section, and the #1 unit diesel generator (18) supplies power to the bus (10) of the #1 unit security PC A section. 17) Check the defects of the #1 unit diesel generator (18), and after eliminating the defects, close the standby incoming line switch (12) of the #1 unit security PC A section, and the #1 unit diesel generator (18) supplies power to the bus (10) of the #1 unit security PC A section. 18) When the fast transfer is blocked due to the grounding fault of the auxiliary bus of Unit 1 and the auxiliary bus of Unit 1 loses power, after the fast transfer device (20) of the auxiliary A section of Unit 1 sends out the action signal of fast transfer blocking, it starts the diesel generator (18) of Unit 1 to build voltage. After the voltage building is successful, the outlet circuit breaker (17) of the diesel generator of Unit 1 is automatically closed, and then it turns to step 6); 19) When the whole plant loses power after Unit 1 and Unit 2 shed loads due to the external line tripping secretly or the line protection tripping, the generator-transformer unit protection device (19) of Unit 1 sends out the zero-power generator tripping protection action signal to start the diesel generator (18) of Unit 1 to build voltage. After the voltage building is successful, the outlet circuit breaker (17) of the diesel generator of Unit 1 is closed, and then it turns to step 6).

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